The present inventions relate generally to code division multiple access (CDMA) communications systems, and more particularly to methods and communications terminals for increasing capacity in CDMA communications systems.
It has been proposed to increase forward link capacity in code division multiple access (CMDA) communication systems by using pilot signal cancellation processing. Intel Corporation, xe2x80x9cCPICH Interference Cancellation as a Means for Increasing Downlink Capacityxe2x80x9d, 3GPP TSG-RAN Working Group, TSGR1-00-1371, November 2000; Intel Corporation, xe2x80x9cFurther Results on CPICH Interference Cancellation as A Means for Increasing DL Capacityxe2x80x9d, 3GPP TSG-RAN Working Group, TSGR1-01-0030, January 2001; Intel Corporation, xe2x80x9cCPICH Interference Cancellation as A Means for Increasing DL Capacityxe2x80x9d, 3GPP TSG-RAN Working Group, TSGR4-01-0238, February 2001.
It is known to subtract reconstructed pilot signals prior to Rake receiver de-spreading and integration as disclosed for example in U.S. Pat. No. 6,009,089 entitled xe2x80x9cPilot Interference Cancellation For A Coherent Wireless Code Division Multiple Access Receiverxe2x80x9d and in U.S. Pat. No. 5,978,413 entitled xe2x80x9cMethod And System For Processing A Plurality of Multiple Access Transmissionsxe2x80x9d. It is also known to subtract pilot channel interference at the symbol rate from the output of the Rake receiver, as disclosed for example in U.S. Pat. No. 6,009,089 entitled xe2x80x9cPilot Interference Cancellation For A Coherent Wireless Code Division Multiple Access Receiverxe2x80x9d, WO 01/05052 entitled xe2x80x9cInterference Suppression In A CDMA Receiverxe2x80x9d, U.S. Pat. No. 5,323,418 entitled xe2x80x9cCode Division Multiple Access Inbound Messaging System Utilizing Interference Cancellation to Recover Inbound Messagesxe2x80x9d, and WO 98/43362 entitled xe2x80x9cMethod And Apparatus For Reducing Spread-Spectrum Noisexe2x80x9d.
There is a 3GPP proposal to ameliorate paging channel interference resulting from the synchronization channel by adopting a moving offset between the synchronization channel and the paging channel. The moving offset however does not reduce the interference, but instead evenly divides it, temporally, among the user equipment (UE). The moving offset moreover does not eliminate interference caused by the synchronization channel to other channels, such as data, which includes voice traffic.
The various aspects, features and advantages of the present invention will become more fully apparent to those having ordinary skill in the art upon careful consideration of the following Detailed Description of the Invention with the accompanying drawings described below.